Method and apparatus for opening letter envelopes

ABSTRACT

Apparatus and methods for opening letter envelopes or the like which comprise a feed hopper adapted to receive a stack of unopened envelopes lying on one another, an output hopper adapted to receive the envelopes after they have been opened, and means for successively transporting individual envelopes from the bottom of the stack in the feed hopper past a cutting means that is adapted to cut a longitudinal edge of the envelopes during transport. The apparatus and methods disclosed also include provision for urging the envelopes against the cutting means during transport, and a vacuum system is utilized for insuring efficient and reliable transporting of the envelopes and for capturing paper particles that are cut from the envelopes as they are opened.

Umted States Patent 1191 1111 3,9

Emkjer et al. [4 Dec. 23, 1975 METHOD AND APPARATUS FOR OPENING2,837,333 6/1958 Sindzinski 61 a! 271/12 1311111 mm 3,130,650 4/1964Shields 271/12 X 3.l3$,l5l 611964 Link et al. 83ll00 X Inventors: ErwmJ- ki 3,381,564 5/1968 Whiteford 83/912 Kenneth 'hlclter, Miami Lakes,both 3,545,136 6/1968 Simjian 83/912 X of Fla. [73] Asignee: KenqnaticCompany I Primary Examiner-J. M. Meister v Plantation, Fla. Attorney,Agent, or Firm-Wolfe, Hubbard, Leydtg, 22 Filed: July 9, 1973 08am [2l]Appl. No.1 377,427 ABSTRACT Dan Apparatus and methods for opening letterenvelopes [63] ContmuauoiHn-part of Ser. No. 275.560. July 27, or thelike which comprise a f hopper adapted to 1972' abandm'ed' receive astack of unopened envelopes lying on one [52] us. 0. 83/23; 83/167;83/3563; m g m fi [511 m 33/4"; 3255325; successively transportingindividual envelopes from d a 3 6 6 6 6 6 v a n v u 6 v v a "g5 6 I I nI n 1 e I n a on in pat a Field Search I167, 356.3, 355, 417,

83/418 912 23 422 27 1mg means that 13 adapted to cut a longitudinaledge l3; Zzuzoz; of the envelopes during transport. The apparatus and53138 R methods disclosed also include provision for urging theenvelopes against the cutting means during trans- [56] References Citedport, and a vacuum system ismtilized for insuring effi- UNITED STATESYATEMS cient and reliable transporting of the envelopes and 1.109.9589/1914 Bryant 83/912 X for capturing paper particles that are cut fromthe en- |,|55,727 3/1915 velopes as they are opened l,408.4l 5 2/ l 922l,$33,l39 4/l925 Putt et a]. 83/3563 16 Claims, 12 Drawing Figures U.S.Patent Dec. 23, 1975 Sheet 1 of4 3,927,589

U.S. Patent Dec. 23, 1975 Sheet 2 of4 3,927,589

U.S. Patent Dec. 23, 1975 Sheet 3 of4 3,927,589

U.S. Patent Dec. 23, 1975 Sheet 4 of4 3,927,589

METHOD AND APPARATUS FOR OPENING LETTER ENVELOPES This application is acontinuation-in-part of our copending parent application Ser. No.275,560, filed July 27, i972. Said parent application Ser. No. 275,560,which is now abandoned, and the present application are assigned to acommon assignee.

This invention relates to letter opening equipment and, moreparticularly, to methods and apparatus for automatically opening letterenvelopes.

It is quite apparent that many companies and institutions that have alarge volume of incoming mail experience considerable lost time andinconvenience in manually opening letter envelopes. In banks and otherinstitutions where hundreds, or even thousands, of letters are receivedvirtually every day, there exists a definite need for apparatus thatwill rapidly and automatically open letter envelopes without damagingtheir contents.

Accordingly, it is an object of the present invention to provideimproved methods and apparatus for reliably and rapidly opening letterenvelopes.

Another object of the present invention is to provide apparatus that isadapted to open envelopes of varying size and which does not requireprecise alignment of the envelopes as they are placed in the feed tray.

Yet another object of the invention is to provide automatic letteropening apparatus which cuts only a small portion of one longitudinaledge of an envelope to open it and thus substantially prohibits damageto the contents of the envelope.

Still another object lies in the provision of a vacuum system thatproduces a suction force for holding the letters being transported tothe output tray or hopper and for capturing the paper particles that arecut from the envelopes during operation.

A more specific object of the present invention is to provide apparatuswhich successively transports individual envelopes from a feed hopper toan output hopper and is adapted to insure contact of one longitudinaledge against the cutting means during the transport of the individualletter envelopes.

Yet another specific object of the present invention is to provideapparatus for reducing the envelope-toenvelope friction of the envelopestack in the feed tray or hopper to insure that the envelopes aresequentially and successively transported past the cutting means.

Still another object of the present invention lies in the provision ofautomatically controlling the apparatus such that the apparatus willautomatically shut down if a jam condition is experienced or when theoutput tray or hopper is full.

An additional object of the present invention is to provide an apparatushaving an auxiliary cutting means which is adapted to open envelopes ofextraordinary size and which are incapable of being transported from thefeed hopper to the output hopper.

These and other objects and advantages of the present invention willbecome apparent from the ensuing specification and drawings, in which:

FIG. 1 is a perspective view of one embodiment of automatic letteropening apparatus incorporating features of the present invention;

FIG. 2 is an exploded perspective view of the appara tus of FIG. 1, withportions removed, and particularly illustrating one form of vacuumsystem itable for use with the present invention;

HO. 3 is a front view of a portion of the apparatus shown by way ofexample in FIG. 1;

FIG. 4 is a top plan view of a portion of the exemplary apparatus shownin FIG. I, here taken generally along the line 44 of FIG. 3;

FIG. 5 is an exploded, fragmentary perspective view, particularlyillustrating the relationship of envelopes, transport belt, and thetransport vacuum manifold in accordance with one exemplary form of theinvention;

FIG. 6 is a partial perspective view, particularly illustrating cuttingmeans and guide means suitable for use with the present invention;

FIG. 7 is a perspective plan view of a portion of the exemplaryapparatus of FIG. I, particularly illustrating the drive means for thetransport belt and cutting means;

FIG. 8 is a sectional view taken substantially along the line 8-8 ofFIG. 3, here particularly illustrating details of the cutter andtransport mechanisms;

FIG. 9 is an exploded, fragmentary perspective view similar to FIG. 5,but here depicting a slightly modified form of the present invention;

FIG. 10 is an enlarged, fragmentary perspective view of a modified formof vacuum system suitable for use with the present invention, here shownwith the front of the housing removed and with the hinged cover open soas to expose the interior portions of the vacuum housing; and

FIGS. 11 and 12 are enlarged fragmentary side and plan viewsrespectively illustrating details of an adjustable bleed mechanismutilized to control the lowvacuum side of the modified form of thesystem shown in FIGS. 9 and 10.

While the present invention is susceptible of various modifications andalternative forms, certain specific embodiments thereof have been shownby way of example in the drawings and will herein be described indetail. It should be understood, however, that it is not intended tolimit the invention to the particular forms disclosed but, on thecontrary, the intention is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the invention asexpressed in the appended claims.

Referring to the drawings and particularly FIGS. 1 and 2, apparatus 10embodying features in accordance with one exemplary form of the presentinvention is shown having a feed hopper or tray 12 for receiving a stackof unopened envelopes 13, an output hopper or tray 14, and a transportmeans indicated generally at 16, which successively advances the lowestletter envelope from the input hopper to the output hopper and, in sodoing, advances the letters past a cutting means which cuts alongitudinal edge from each of the envelopes as they are transported.The apparatus 10 has a centrally located control panel, indicatedgenerally at 20, which controls the operation of the apparatus and alsoprovides a visual monitor for indicating the various running conditionsat any time.

To transport the letter envelopes from the feed hopper to the outputhopper, and referring to FIGS. 2 and 3, a flexible endless belt 22 isprovided which moves in a generally flat elongated loop, the upperportion of which extends from a point adjacent the lower left wall ofthe feed hopper 12 to a point adjacent the edge of the output hopper 14.The belt is positioned at an angle relative to a horizontal plane asshown in FIG. 3 so that the lowermost letter envelope being transportedfrom the feed hopper will exit into the upper portion of the outputhopper to enable accumulation of letters in the output hopper. Atransport vacuum manifold 24 is provided immediately adjacent the upperportion of the loop and is adapted to communicate a vacuum supply to theunderside of the upper flight of the belt 22. As best shown in FIG. 5,the manifold 24 is rectangular in cross section and has a narrow slot 25extending substantially its entire length. The belt 22 is in turnprovided with a number of apertures 26 which are in alignment with theslot 25 in the manifold 24 and thereby communicates vacuum to theenvelopes being transported and proveds a holding force to insure thatthe letter envelopes are held to the belt and will thereby be advancedas the belt moves.

In keeping with an important aspect of one embodiment of the presentinvention and referring to FIGS. 2 and 5, the apertures 26 arepreferably placed a predeten'nined distance from each side of a raisedfrictional surface 27 which may be latex rubber or the like. As soon asa pair of apertures 26 reach the upper portion of the endless loopduring movement of the belt, the vacuum will engage the lowest envelopeand advance it out of the feed hopper. The distance between adjacentraised surfaces 27 is greater than the average length of a businessenvelope, for example to 16 inches, so that as the belt moves theenvelopes will be transported past the cutting means to the output traywith a reasonable spacing between adjacent envelopes.

While the shape of each of the raised surfaces 27 is not particularlycritical and is shown in FIGS. 2 and 5 to be of a small circularconfiguration, it is important that the height of the surfaces be withinthe range of approximately l/l6 to A; inch so that as the belt advancesand one of the raised surfaces comes into contact with the underside ofthe stack of envelopes 13 in the feed hopper, that it jar or jostle thestack. This is important in reducing the envelope-to-envelope frictionthat is present in the stack of envelopes I3 and enables the lowestenvelope to be transported to the moving belt 22. In this connection, ithas been observed that the vacuum force communicated through theapertures 26 is often insufficient to break away" a single lowermostenvelope from the stack in the absence of a raised frictional surfacesuch as the surface 27. It is also important in this embodiment of theinvention that the distance between the surface 27 and the adjacentapertures 26 be at least about 1 inch and preferably between inch and 2inches so that the raised surfaces will not interfere with the vacuumforce holding the envelopes to the belt. It has been found that mostletter envelopes are sufficiently flexible so that they will be held bythe vacuum being communicated through the apertures when a Va inch highraised surface is used together with a 1% inch spacing between theraised surface and each of the apertures.

In the event the envelope-to-envelope friction in the feed hopper is notcompletely overcome by the jarring effect of the raised surface 27 ofthe transport belt, and two letters are simultaneously advanced, abracket 28 having flexible rubber member 29 is located adjacent theopening in the feed hopper for the purpose of restraining the envelopethat is riding on top of the lowermost envelope from being transportedout of the feed tray 12 until the lower-most envelope has exited thefeed tray.

Turning now to FIGS. 2, 6 and 8 it is preferred that the width of thebelt 22 be less than the width of the envelopes being opened and,accordingly. a support transport guide 30 is provided in the same planeas the upper portion of the belt loop. A rear generally verticaltransport guide 32 having an angled portion 34 is also provided toaccurately position the envelopes as they pass the cutting means. Therear guide angled portion 34 is positioned immediately adjacent thesupporting transport guide 30 and provides a downward component of forcethat tends to prevent the letter envelopes from climbing up the reartransport guide 32 during movement and thereby escape engagement withthe cutting means.

To cut the longitudinal edge of the envelopes being transported, acircular toothed slitting or cutting saw is illustrated in FIG. 6,although an abrasive wheel or the like may be provided. The cutting sawis preferably about 3 inches in diameter and is rotated so that thecutting action is downwardly toward the support transport guide 30during engagement with the envelope being opened. With the slitting sawrotating in this direction, the supporting transport guide functionsmuch the same as an anvil and insures a uniform cutting action. As isclearly illustrated in FIG. 6, an opening 38 is provided in the angledportion 34 of the rear transport guide 32 and extends into the supporttransport guide 30 a predetermined distance. The cutting saw 36 ispreferably positioned so that the outer periphery thereof extends beyondthe rear transport guide a small distance. for example, about 300ths ofan inch to insure that the cutting saw does not damage the contents ofthe letter being opened.

In keeping with the invention, the speed of the rotation of the cuttingsaw is preferably within the range of 5000 to 7000 rpm so that a cleancut of the longitudinal edge is made without providing excessiveresistance to the movement of the letter being transported. To this end,it has been found with a 3 inch diameter cutting saw, that rotationalspeeds less than 5000 rpm have generated sufficient resistance tomovement that a jam condition has often occurred. It should beunderstood that preferred rotational velocities would be somewhatdifferent depending upon the diameter of the saw being used. It is alsopreferred that the axis of the slitting saw 36 be slightly above thesupporting transport guide 30, for example, about one to two tenths ofan inch. As is best shown in FIG. 3, the plane of the cutting saw 36 isperpendicular to the plane of the transport belt 22.

In accordance with another important aspect of the present invention,the transport belt 22 is positioned at an angle relative to the reartransport guide 32 as best shown in FIGS. 4 and 6, and is so positionedto urge the envelope into contact with the rear transport guide andtherefore the cutting saw. While the angle is not deemed critical, anddepends in part upon such factors as the distance between the feed andoutput hoppers, the exact placement of the cutting saw relative to thelength of travel during transport and the like, the angle illustrated ispreferably within the range of about l0 to 20. and is specificallyillustrated to be about [5". It should be understood that letters can beplaced in the feed hopper with some degree of misalignment so that whenthey are advanced by the transport belt. the angular orientation of thebelt relative to the guide wall will urge the letter toward the reartransport guide 32 and thus insure contact of the longitudinal edge ofthe envelope with the cutting saw and thereby insure a generally uniformand reliable cutting action. In this connection, it was previouslymentioned that the transport belt extended from a point adjacent or nearthe left edge of thereof. It should be understood that engagement by oneof the raised surfaces at a location ahead of the center line of theenvelope would frequently urge only the forward edge against the reartransport guide and the rear portion of the envelope would remain awayfrom it, since no force would be applied to the rear portion tending tourge it to firmly abut against the rear transport guide.

ln keeping with yet another aspect of the present invention, thetransport belt also has its edge near the front of the apparatusslightly higher than the opposite edge. As best shown in FIG. 2, thebelt is positioned at an angle of about l5 along the entire upperportion of the loop around which it travels. This angular orientationhas the effect of utilizing a component of gravitational force to moreaccurately align the letters in the Z5 feed tray since the continuousjostling of the letters by the raised surfaces tends to cause theletters to become more accurately aligned as they reach the lowerposition in the feed hopper or tray.

In keeping with the invention provision is made for opening envelopes ofextraordinary size by the placement of a second cutting saw 40 near thefront center portion of the apparatus. The cutting saw 40 is positionedadjacent a horizontal slot 42 which acts as a guide enabling an operatorto place an edge of an envelope into the slot and slide it into contactwith the cutting saw and thereby open the envelope. The cutting saw ispreferably of substantially similar constructions as the cutting saw 36previously described. To

drive the cutting saws 36 and 40, an electric motor or 40 the like 44 isprovided with an output shaft 46 having a pair of pulleys 48, 50attached thereto which drive flexible belts 52, 54 or the like whichalso ride on pulleys 56, 58 associted with the cutting saws 40 and 36,

respectively, as shown in FIGS. 3 and 7.

To drive the transport belt 22, another electric motor 60 or the like,is provided and has a pulley 62 attached to its drive shaft 64. A belt66 rides on the pulley 62 as well as another pulley 68 that is attachedto a shaft 70 which also has a drive roller 72 for driving the transportbelt 22. At the opposite end of the elongated loop is a second freelyrotatable roller 74 around which the transport belt is driven. Since theapparatus is designed for rapid operation, and will open up to 450envelopes per minute, the transport belt moves the envelopes quiterapidly. Because of the upward inclination of the belt, one or moreflexible deflectors 76 may be advantageously attached. near the outputhopper to downwardly deflect the envelopes so that they will enter theoutput hopper.

Turning now to the vacuum system associated with the embodiment of theinvention heretofore described, a vacuum motor (not shown) is located inan enclosure 80 positioned toward the rear of the apparatus, as

shown in FIG. 2. The motor is preferably of a size which will generatesufflcient vacuum to adequately hold the letters to the transport beltas well as provide a capability for capturing the paper particles thatare cut from the envelopes during operation. In this connection, forexample. a l horsepower electric vacuum *pro'ducing source capable ofproducing a vacuum of 'enclosure which preferably has a bag 97 thereinto capture the particles.

Another flexible conduit or hose 96 may be provided to communicatevacuum to the back wall of the output hopper for the purpose of insuringcorrect alignment of a letter envelope receiving carton 98 which may beplaced in the output hopper. It should be understood that if the carton98 is not aligned with the opened envelopes being transported to theoutput hopper. the letters may strike the side walls of the carton andproduce a jam condition in a very short time. The vacuum force willcorrect any slight misalignment caused by an operator who may havefailed to accurately position the carton during its insertion into theoutput hopper.

In keeping with the present invention, the exemplary apparatus has anelectrical control system which is of conventional design and thereforehas not been shown in detail. Referring to FIG. I, the control panel 20includes a resettable counter 102, thumbwheel switches 103 forpreselecting the quantity of open envelopes to be delivered to theenvelope receiving carton 98, a main power switch 104, a cutter switch106, a transport switch 108, full indicator light and a jam indicatorlight 112. To start the apparatus, the operator merely inserts a stackof letters in the input of feed hopper, depresses the main power switch,which must be on for any of the motors to be operable. The operator thendepresses the cutter switch which turns on the vacuum system as well asthe cutter drive motor 44. Afler the cutter switch 106 is turned on. theoperator merely depresses the transport switch 108 which turns on motor60 and causes the transport belt 22 to begin moving. Referring to FIG.3, a jam indicator circuit comprising a light source 114 and aphotoelectric sensor 116 is positioned immediately adjacent thetransport belt near the output hopper 14. A timing circuit is associatedwith the photoelectric circuit so that a jam condition will not beindicated unless a letter envelope opens the photoelectriccircuit for apredetermined time which is longer than the time necessary for a singleletter to pass during operation. If, for example, a jam condition isexperienced, the envelopes will block the photoelectric circuit for atime longer than should be required and this condition will cause thetransport motor 60, the cutter motor 44 and the vacuum system to shutoff. A second photoelectric circuit comprising a photocell [l8 andanother light source (not shown) is positioned near the upper portion ofthe output hopper and is effective to indicate when the carton 98 isfull. Breakage of the photoelectric circuit will shut off the transportmotor and thereby stop feeding of envelopes through the apparatus. Atthis point, the operator may remove the filled carton of openedenvelopes, insert another carton. and depress the transport buttoncausing the continued operation of the 7 apparatus.

While the invention has heretofore been described in connection with anembodiment utilizing a raised frictional surface--e.g., the surface asshown in FIG. -interposed between a pair of vacuum transmittingapertures 26, it is not limited to that specific construction and otherembodiments may be employed to effect the desired jostling of the stackof envelopes in the feed hopper 12 of FIG. 1. For example, analternative construction that has been found to be quite satisfactory isillustrated by way of example in FIG. 9.

In accordance with this altgmative form of the invention as shown inFIG. 9, the endless transport belt 22 is provided with a series ofvacuum transmitting apertures spaced apart by a distance somewhatgreater than the average length of a business enveIope--for example, 15to 16 inches apart--one such aperture being depicted in FIG. 9 at 120. Araised friction surface, here in the form of a flat square pad 121 ofnatural rubber or the like having a central aperture I22 somewhat largerthan the belt aperture 120, is bonded to the belt 22 with the twoapertures I20, 122 being coaxial. As in the form of the inventionheretofore described in connection with FIG. 5, the particulardimensions employed are not critical, but advantageous results have beenobtained utilizing a pad 12] approximately l /zinches square, l/l6 to V5inch high, and having an aperture 122 witha 1 inch diameter coaxial witha 5% inch diameter aperture 120 in the belt 22.

It will be appreciated upon comparison of the embodiment of theinvention shown in FIG. 5 with that shown in FIG. 9 that, whereas theformer provides a pair of vacuum transmitting apertures on either sideof a raised frictional surface, the latter provides raised frictionalsurfaces on either side of a vacuum transmitting aperture. In bothcases, however, the net effect is that the raised frictional surfacetends to jostle the stack of envelopes in the feed hopper (e.g., hopper12 in FIG. I) so as to separate the lowermost envelope from the stack,while the aperture(s) pennits communication of sufiicient vacuum tofirmly clamp the lowennost envelope 13 to the belt 22.

In order to permit even more envelopes 13 to be stacked in the feedhopper 12 (FIG. I), while at the e time insuring efficient and reliableremoval of the lo'wermost envelope from the stack and subsequentprocessing thereof irrespective of whether the system is being utilizedto open relatively stiff envelopes of relatively thin, light-weightenvelopes, a modified vacuum system such as illustrated in FIGS. 9-12may be employed.

In keeping with this form of the invention, provision is made forallowing a relatively high vacuum to be communicated to the envelopebeing stripped from the bottom of the stack in the feed hopper, and arelatively lower vacuum to be communicated to the envelope as itprogresses along the transport mechanism. To this end, and as bestillustrated in FIG. 9, the transport vacuum manifold 24 is againprovided with a narrow slot 25 extending substantially its entirelength. However, in this form of the invention, the manifold 24 isprovided with a transverse baffle 124 at approximately the midpoint,thus dividing the manifold into two separate chambers--viz., arelatively high vacuum chamber 125 and a relatively low vacuum chamberI26. The arrangement is such that as the belt 22 moves along its endlesspath, a raised surface thereon will engage the stack of envelopes I3 inthe feed hopper 12 (FIG. 1),

thereby jostling the stack and separating the lowermost envelopetherefrom. Relatively high vacuum will be communicated from chamberthrough the coaxial apertures I20, I22 (or through the pair of apertures26 if this modified vacuum system is used with the belt shown in FIG. 5)to firmly clamp the envelope to the belt and strip it from the stack.This permits more envelopes to be stacked in the feed hopper 12 (FIG.I).

In carrying out this modified form of the invention, a vacuum motor I28is located in an enclosure 129, as best shown in FIG. 10. As the ensuingdescription proceeds, it will be understood that the enclosure 129 shownin FIG. I0 and the vacuum system contained therein is somewhat similarin function and intended to replace the enclosure 80 and associatedvacuum system previously described in connection with FIG. 2. Thearrangement is such that the relatively high vacuum drawn by motor 128is communicated through a hose or flexible conduit 130 directlyconnecting the motor 128 (FIG. 10) to the high vacuum chamber 125 (FIG.9) in the transport manifold 24. At the same time, the relatively highvacuum drawn by the motor I28 is also communicated to a closed chamber(FIG. I0) located within enclosure I29 through a port 132. Those skilledin the art will appreciate that while the chamber I31 is shown open inFIG. 10, during operation of the equipment the cover 134 of theenclosure 120 would be moved to the closed position, thereby closingchamber 131. 4

In keeping with this aspect of this invention provision is made forcontrollably regulating the degree of vacuum maintained within chamber131. To accomplish this, an adjustable vacuum regulator, generallyindicated at I35 (FIG. 10-12), is mounted in the cover 134 forpermitting controlled bleeding of ambient air into the chamber 131,thereby controllably reducing the vacuum level therein. In the(exemplary system, the regulator 135 comprises a metalbacked rubber disc136 which is slidably mounted on a bolt 138 that passes through thecover 135 coaxial with a circular array of bleed ports I39 fonned in thecover. The disc 136 is adjustably biased into contact with the bottom ofthe cover 134 in underlying sealing relation to the ports I39 by meansof a spring 140 which surrounds the bolt I38 and is bottomed at itsupper end on the under surface of the disc I36 and at its lower end on anut I41 threadably engaged with the bolt 138. By threading the nut I41onto the bolt 138, the spring I40 is compressed, thereby increasing thepressure with which the pad I36 is urged into sealing relation with thebleed ports 139, reducing the flow of ambient air into the chamber I31,and thus increasing the vacuum level maintained in the chamber.Conversely, when the nut 141 is unthreaded, the spring is extended,thereby reducing the pressure with which the pad is urged into sealingengagement with the ports 139. This serves to let atmospheric pressureovercome, to a contollable extent dependent upon the spring tension, thespring bias, thereby permitting a controlled amount of air to bleed intochamber 131 and reducing the vacuum level therein. The controlled andreduced vacuum level is then communicated to the relatively low vacuumchamber 126 in the transport manifold 24 by means of a hose or otherflexible conduit I42 (FIGS. 9 and 10).

It has been found in the practice of the present invention that thearrangement of a 1 inch diameter aperture (FIG. 9) in the raisedfrictional surface 121 overlying and coaxial with a /2 inch diameteraperture 120 in the belt 22, permits the envelope 13 being transportedto be firmly clamped to the belt while, at the same time, there is arapid transition from high to low vacuum as the apertures 120, 122 passthe baffle [24 separating the chambers [25 and 126. Moreover, theprovision of the low vacuum side of the system imparts greaterflexibility to the system since it can be more readily used with thin,light-weight envelopes.

In keeping with the present invention, the enclosure [29 serves also tohouse a vacuum bag 144 (FIG. coupled to a second vacuum motor 145. Thevacuum drawn in the bag 144 is communicated to a manifold 146 having aplurality of hose connections; for example, connections 148, 149 and150. The connections 148, 149 may be coupled directly to hoses (such asthe hoses 92, 94 shown in FIG. 2) for removal of chips fonned duringenvelope cutting operations; such chips being collected in the bag 144for subsequent discarding. Similary, the connection 150 may be coupleddirectly to a hose (sucy as the hose 96 shown in FIG. 2) for holding theenvelope container 98 in place as previously described.

Thus, it should be readily apparent that automatic letter envelopeopening apparatus and methods have been described which provide reliableand fast operation and which satisfy all of the aforementioned objectsand advantages.

We claim as our invention:

1. Apparatus for opening letter envelopes or the like, comprising, incombination:

a feed hopper adapted to receive a stack of unopened envelopes lying onone another;

an output hopper adapted to receive said envelopes after they have beenopened;

a flexible transport belt movable around a loop, the upper portion ofwhich extends from beneath the upstream side of said feed hopper to apoint adjacent said output hopper for successively transportingindividual envelopes from the bottom of said stack in said feed hopperto said output hopper;

means for guiding said envelopes as they are transported to said outputhopper, said guide means including a support transport guide portionlying substantially in the same plane as said upper portion of said beltand a generally vertical rear transport guide portion intersecting saidsupport guide portion for accurately positioning said envelopes forengagement with said cutting means during movement of said envelopes,said generally vertical rear transport guide portion having a portionnear said support guide portion that is positioned at an acute anglerelative to said support guide portion so that said envelopes arerestrained from moving upwardly from said support guide portion duringtransport thereof;

means for cutting a longitudinal edge of said envelopes as they aretransported to said output hopper, said cutting means being locatedadjacent said guide means;

means for urging said longitudinal edge of said envelope to firmly abutagainst said guide means during transport to insure substantiallycomplete cutting of said longitudinal edge; and

a vacuum manifold and a vacuum supply connected thereto, said manifoldbeing positioned immediately below the upper portion of said loop andextending longitudinally from a point below said stack in said feedhopper to a point beyond said 10 cutting means, said belt including atleast one aperture therein for communicating vacuum to said envelopesfor holding said envelopes to said belt during transport thereof fromsaid feed hopper stack, past said cutting means, and to a point beyondsaid cutting means.

2. Apparatus as defined in claim 1 wherein said transport belt is angleddownwardly toward the rear of said apparatus so that envelopes in saidfeed hopper tend to move toward the rear thereof due to the jostlingaction caused by the raised surfaces contacting the bottom of saidstack.

3. Apparatus for opening letter envelopes or the like,

comprising, in combination:

a feed hopper adapted to receive a stack of unopened envelopes lying onone another;

an output hopper adapted to receive said envelopes after they have beenopened;

a flexible transport belt movable around a loop, the upper portion ofwhich extends from beneath the upstream side of said feed hopper to apoint adjacent said output hopper for successively transportingindivdual envelopes from the bottom of said stack in said feed hopper tosaid output hopper;

means for guiding said envelopes as they are transported to said outputhopper;

means for cutting a longitudinal edge of said envelopes as they aretransported to said output hopper, said cutting means being locatedadjacent said guide means;

means for urging said longitudinal edge of said envelope to firmly abutagainst said guide means during transport to insure substantiallycomplete cutting of said longitudinal edge; and

a vacuum manifold and a vacuum supply connected thereto, said manifoldbeing positioned immediately below the upper portion of said loop andextending longitudinally from a point below said stack in said feedhopper to a point beyond said cutting means,

said belt being formed with pairs of apertures for communicating vacuumto said envelopes for holding said envelopes to said belt duringtransport thereof from said feed hopper stack, past said cutting means,and to a point beyond said cutting means, said apertures of each pairbeing located in predetermined relation on opposite sides of a raisedfrictional surface, said raised surfaces being spaced apart from oneanother along the length of said belt a predetermined distance which isgreater than the length of said envelopes, said raised surfaces beingeffective to jostle said stack of envelopes in said supply hopper duringmovement of said belt to reduce the envelope-to-envelope friction withinsaid stack and enable the lowermost envelope to be transported towardsaid output hopper.

4. Apparatus as defined in claim 3 wherein said predetermined distanceis within the range of about 1 and 2 inches.

5. Apparatus for opening letter envelopes or the like, comprising, incombination:

a feed hopper adapted to receive a stack of unopened envelopes lying onone another;

an output hopper adapted to receive said envelopes after they have beenopened;

a flexible transport belt movable around a loop, the upper portion ofwhich extends from beneath the 1 l upstream side of said feed hopper toa point adjacent said output hopper for successively transportingindividual envelopes from the bottom of said stack in said feed hopperto said output hopper; means for guiding said envelopes as they aretransported to said output hopper;

means for cutting a longitudinal edge of said envelopes as they aretransported to said output hopper. said cutting means being locatedadjacent said guide means;

said belt being positioned at an acute angle relative to said guidemeans so that said longitudinal edge of each of said envelopes is urgedagainst said guide means during transport to insure substantiallycomplete cutting of said longitudinal edge;

a vacuum manifold and a vacuum supply connected thereto. said manifoldbeing positioned immediately below the upper portion of said loop andextending longitudinally from a point below said stack in said feedhopper to a point beyond said cutting means, said belt including atleast one aperture therein for communicating vacuum to said envelopesfor holding said envelopes to said belt during transport thereof fromsaid feed hopper stack, past said cutting means, and to a point beyondsaid cutting means; and

a thin pad bonded to said belt and having an aperture therein coaxialwith the aperture in said belt, said pad forming a raised frictionalsurface for jostling said stack of envelopes in said supply hopperduring movement of said belt so as to reduce the envelope-to-envelopefriction within said stack and enable the lowermost envelope to betransported toward said output hopper.

6. Apparatus as defined in claim 5 wherein the aper ture in said pad islarger than the aperture in said belt.

7.. Apparatus as defined in claim 6 wherein the aperture in said pad ison the order of one inch in diameter and the aperture in said belt is onthe order of one-half inch in diameter.

8. Apparatus for opening letter envelopes or the like.

comprising, in combination:

a feed hopper adapted to receive a stack of unopened envelopes lying onone another;

an output hopper adapted to receive said hopper envelopes after theyhave been opened;

a flexible transport belt movable around a loop, the upper portion ofwhich extends from beneath the upstream side of said feed hopper to apoint adjacent said output hopper for successively transportingindividual envelopes from the bottom of said stack in said feed hopperto said output hopper;

means for guiding said envelopes as they are transported to said outputhopper;

means for cutting a longitudinal edge of said envelopes as they aretransported to said output hopper. said cutting means being locatedadjacent said guide means;

means for urging said longitudinal edge of said envelope to firmly abutagainst said guide means during transport to insure substantiallycomplete cutting of said longitudinal edge;

a vacuum manifold fomied with two chambers, said chambers each beingconnected to a vacuum supply, said manifold being positioned immediatelybelow the upper portion of said loop and extending longitudinally from apoint below said stack in said feed hopper to a point beyond saidcutting means (ill with one of said chambers being at the feed hopperend of said manifold and the other of said chambers being at theopposite end of said manifold, said chamber at the feed hopper end ofsaid manifold being maintained at a higher vacuum level than the chamberat the opposite end of said manifold. and

said belt including at least one aperture therein for communicatingvacuum to said envelopes for holding said envelopes to said belt duringtransport thereof from said feed hopper stack, past said cutting means,and to a point beyond said cutting means.

9. Apparatus as defined in claim 8 wherein an enclosure connected tosaid vacuum supply is positioned adjacent said cutting means so thatpaper particles removed from said envelopes during opening thereof arecaptured.

10. Apparatus as defined in claim 8 wherein the vacuum level in saidother chamber is adjustable.

11. Apparatus as defined in claim 8 wherein said two vacuum chambers areconnected to a common vacuum supply.

12. Apparatus as defined in claim 1 wherein an adjustable vacuumregulator is included in the connection between said vacuum supply andsaid other chamber.

13. Apparatus for opening letter envelopes or the like, comprising, incombination:

a feed hopper adapted to receive a stack of unopened envelopes lying onone another;

an output hopper adapted to receive said envelopes after they have beenopened;

means for successively transporting individual envelopes from the bottomof said stack in said feed hopper to said output hopper;

means for guiding said envelopes as they are transported to said outputhopper;

a cutting saw positoned adjacent said guide means and being rotatable ina direction downwardly toward said envelopes for cutting off thelongitudinal edges thereof;

means for urging the longitudinal edges of said envelopes to firmly abutagainst said guide means during transport to insure substantiallycomplete cutting of said longitudinal edge; and

an auxiliary cutting wheel at the front of said apparatus for cutting alongitudinal edge of envelopes of extraordinary size.

14. Apparatus as defined in claim 13 wherein said belt is positioned atan acute angle relative to said guide means so that said longitudinaledge of each of said envelopes is urged against said guide means priorto reaching said cutting means during transport to said output hopper.

15. A method of opening letter envelopes or the like, comprising thesteps of: the envelopes lying on one another;

advancing a flexible belt around an elongated closed loop, said belthaving one or more apertures formed therein, said belt also having oneor more raised surfaces thereon adapted to jostle the bottom of thestack and reduce the envelope-toenvelope friction enabling the lowermostenvelopes to be successively transported out of said feed hopper;

moving said belt about said loop in such manner that it converges towarda guide means during its advancement and thereby urges said envelopesinto contact with said guide means to accurately position said envelopesfor cutting a lodgtidinal edge therefrom;

cutting a longitudinal edge of said envelopes as they are advanced andthereby opening said envelopes;

depositing said opened envelopes in an output hopper; and applying asuction force only through apertures in said belt located at pointsrearwardly of the transverse center line of each said envelope so thatthe envelopes are held to said belt as said belt advances the envelopesfrom said feed hopper and the entire longitudinal edge of each envelopeis urged against said guide means as the belt advances the envelopesthrough said cutting operation and to a point in the vicinity of saidoutput hopper.

16. A method of opening letter envelopes or the like,

comprising the steps of:

placing a stack of unopened envelopes in a feed hopper with theenvelopes lying on one another;

advancing a flexible belt around an elongated closed loop, said belthaving one or more raised surfaces therein adapted to jostle the bottomof the stack and reduce the envelope-to-envelope friction enabling thelowermost envelopes to be successively transported out of said feedhopper;

urging said envelopes against a guide means to accurately position saidenvelopes and enable a longitudinal edge to be cut therefrom;

cutting a longitudinal edge of said envelopes as they are advanced andthereby opening said envelopes;

depositing said opened envelopes in an output hopper;

applying a suction force through one or more apertures in said belt tohold said envelopes against said belt as said belt advances theenvelopes from said feed hopper, through said cutting operation, and toa point in the vicinity of said output hopper; and

applying a greater suction force to said envelopes in the vicinity ofsaid feed hopper than in the vicinities of said cutter and outputhopper.

1. Apparatus for opening letter envelopes or the like, comprising, incombination: a feed hopper adapted to receive a stack of unopenedenvelopes lying on one another; an output hopper adapted to receive saidenvelopes after they have been opened; a flexible transport belt movablearound a loop, the upper portion of which extends from beneath theupstream side of said feed hopper to a point adjacent said output hopperfor successively transporting individual envelopes from the bottom ofsaid stack in said feed hopper to said output hopper; means for guidingsaid envelopes as they are transported to said output hopper, said guidemeans including a support transport guide portion lying substantially inthe same plane as said upper portion of said belt and a generallyvertical rear transport guide portion intersecting said support guideportion for accurately positioning said envelopes for engagement withsaid cutting means during movement of said envelopes, said generallyvertical rear transport guide portion having a portion near said supportguide portion that is positioned at an acute angle relative to saidsupport guide portion so that said envelopes are restrained from movingupwardly from said support guide portion during transport thereof; meansfor cutting a longitudinal edge of said envelopes as they aretransported to said output hopper, said cutting means being locatedadjacent said guide means; means for urging said longitudinal edge ofsaid envelope to firmly abut against said guide means during transportto insure substantially complete cutting of said longitudinal edge; anda vacuum manifold and a vacuum supply connected thereto, said manifoldbeing positioned immediately below the upper portion of said loop andextending longitudinally from a point below said stack in said feedhopper to a point beyond said cutting means, said belt including atleast one aperture therein for communicating vacuum to said envelopesfor holding said envelopes to said belt during transport thereof fromsaid feed hopper stack, past said cutting means, and to a point beyondsaid cutting means.
 2. Apparatus as defined in claim 1 wherein saidtransport belt is angled downwardly toward the rear of said apparatus sothat envelopes in said feed hopper tend to move toward the rear thereofdue to the jostling action caused by the raised surfaces contacting thebottom of said stack.
 3. Apparatus for opening letter envelopes or thelike, comprising, in combination: a feed hopper adapted to receive astack of unopened envelopes lying on one another; an output hopperadapted to receive said envelopes after they have been opened; aflexible transport belt movable around a loop, the upper portion ofwhich extends from beneath the upstream side of said feed hopper to apoint adjacent said output hopper for successively transportingindivdual envelopes from the bottom of said stack in said feed hopper tosaid output hopper; means for guiding said envelopes as they aretransported to said output hopper; means for cutting a longitudinal edgeof said envelopes as they are transported to said output hopper, saidcutting means being located adjacent said guide means; means for urgingsaid longitudinal edge of said envelope to firmly abut against saidguide means during transport to insure substantially complete cutting ofsaid longitudinal edge; and a vacuum manifold and a vacuum supplyconnected thereto, said manifold being positioned immediately below theupper portion of said loop and extending longitudinally from a pointbelow said stack in said feed hopper to a point beyond said cuttingmeans, said belt being formed with pairs of apertures for communicatingvacuum to said envelopes for holding said envelopes to said belt duringtransport thereof from said feed hopper stack, past said cutting means,and to a point beyond said cutting means, said apertures of each pairbeing located in predetermined relation on opposite sides of a raisedfrictional surface, said raised surfaces being spaced apart from oneanother along the length of said belt a predetermined distance which isgreater than the length of said envelopes, said raised surfaces beingeffective to jostle said stack of envelopes in said supply hopper duringmovement of said belt to reduce the envelope-to-envelope friction withinsaid stack and enable the lowermost envelope to be transported towardsaid output hopper. Pg,22
 4. Apparatus as defined in claim 3 whereinsaid predetermined distance is within the range of about 1 and 2 inches.5. Apparatus for opening letter envelopes or the like, comprising, incombination: a feed hopper adapted to receive a stack of unopenedenvelopes lying on one another; an output hopper adapted to receive saidenvelopes after they have been opened; a flexible transport belt movablearound a loop, the upper portion of which extends from beneath theupstream side of said feed hopper to a point adjacent said output hopperfor successively transporting individual envelopes from the bottom ofsaid stack in said feed hopper to said output hopper; means for guidingsaid envelopes as they are transported to said output hopper; means forcutting a longitudinal edge of said envelopes as they are transported tosaid output hopper, said cutting means being located adjacent said guidemeans; said belt being positioned at an acute angle relative to saidguide means so that said longitudinal edge of each of said envelopes isurged against said guide means during transport to insure substantiallycomplete cutting of said longitudinal edge; a vacuum manifold and avacuum supply connected thereto, said manifold being positionedimmediately below the upper portion of said loop and extendinglongitudinally from a point below said stack in said feed hopper to apoint beyond said cutting means, said belt including at least oneaperture therein for communicating vacuum to said envelopes for holdingsaid envelopes to said belt during transport thereof from said feedhopper stack, past said cutting means, and to a point beyond saidcutting means; and a thin pad bonded to said belt and having an aperturetherein coaxial with the aperture in said belt, said pad forming araised frictional surface for jostling said stack of envelopes in saidsupply hopper during movement of said belt so as to reduce theenvelope-to-envelope friction within said stack and enable the lowermostenvelope to be transported toward said output hopper.
 6. Apparatus asdefined in claim 5 wherein the aperture in said pad is larger than theaperture in said belt. 7.. Apparatus as defined in claim 6 wherein theaperture in said pad is on the order of one inch in diameter and theaperture in said belt is on the order of one-half inch in diameter. 8.Apparatus for opening letter envelopes or the like, comprising, incombination: a feed hopper adapted to receive a stack of unopenedenvelopes lying on one another; an output hopper adapted to receive saidhopper envelopes after they have been opened; a flexible transport beltmovable around a loop, the upper portion of which extends from beneaththe upstream side of said feed hopper to a point adjacent said outputhopper for successively transporting individual envelopes from thebottom of said stack in said feed hopper to said output hopper; meansfor guiding said envelopes as they are transported to said outputhopper; means for cutting a longitudinal edge of said envelopes as theyare transported to said output hopper, said cutting means being locatedadjacent said guide means; means for urging said longitudinal edge ofsaid envelope to firmly abut against said guide means during transportto insure substantially complete cutting of said longitudinal edge; avacuum manifold formed with two chambers, said chambers each beingconnected to a vacuum supply, said manifold being positioned immediatelybelow the upper portion of said loop and extending longitudinally from apoint below said stack in said feed hopper to a point beyond saidcutting means with one of said chambers being at the feed hopper end ofsaid manifold and the other of said chambers being at the opposite endof said manifold, said chamber at the feed hopper end of said manifoldbeing maintained at a higher vacuum level than the chamber at theopposite end of said manifold, and said belt including at least oneaperture therein for communicating vacuum to said envelopes for holdingsaid envelopes to said belt during transport thereof from said feedhopper stack, past said cutting means, and to a point beyond saidcutting means.
 9. Apparatus as defined in claim 8 wherein an enclosureconnected to said vacuum supply is positioned adjacent said cuttingmeans so that paper particles removed from said envelopes during openingthereof are captured.
 10. Apparatus as defined in claim 8 wherein thevacuum level in said other chamber is adjustable.
 11. Apparatus asdefined in claim 8 wherein said two vacuum chambers are connected to acommon vacuum supply.
 12. Apparatus as defined in claim 1 wherein anadjustable vacuum regulator is included in the connection between saidvacuum supply and said other chamber.
 13. Apparatus for opening letterenvelopes or the like, comprising, in combination: a feed hopper adaptedto receive a stack of unopened envelopes lying on one another; an outputhopper adapted to receive said envelopes after they have been opened;means for successively transporting individual envelopes from the bottomof said stack in said feed hopper to said output hopper; means forguiding said envelopes as they are transported to said output hopper; acutting saw positoned adjacent said guide means and being rotatable in adirection downwardly toward said envelopes for cutting off thelongitudinal edges thereof; means for urging the longitudinal edges ofsaid envelopes to firmly abut against said guide means during transportto insure substantially complete cutting of said longitudinal edge; andan auxiliary cutting wheel at the front of said apparatus for cutting alongitudinal edge of envelopes of extraordinary size.
 14. Apparatus asdefined in claim 13 wherein said belt is positioned at an acute anglerelative to said guide means so that said longitudinal edge of each ofsaid envelopes is urged against said guide means prior to reaching saidcutting means during transport to said output hopper.
 15. A method ofopening letter envelopes or the like, comprising the steps of: theenvelopes lying on one another; advancing a flexible belt around anelongated closed loop, said belt having one or more apertures formedtherein, said belt also having one or more raised surfaces thereonadapted to jostle the bottom of the stack and reduce theenvelope-to-envelope friction enabling the lowermost envelopes to besuccessively transported out of said feed hopper; moving said belt aboutsaid loop in such manner that it converges toward a guide means duringits advancement and thereby urges said envelopes into contact with saidguide means to accurately position said envelopes for cutting alongtidinal edge therefrom; cutting a longitudinal edge of saidenvelopes as they are advanced and thereby opening said envelopes;depositing said opened envelopes in an output hopper; and applying asuction force only through apertures in said belt located at pointsrearwardly of the transverse center line of each said envelope so thatthe envelopes are held to said belt as said belt advances the envelopesfrom said feed hopper and the entire longitudinal edge of each envelopeis urged against said guide means as the belt advances the envelopesthrough said cutting operation and to a point in the vicinity of saidoutput hopper.
 16. A method of opening letter envelopes or the like,comprising the steps of: placing a stack of unopened envelopes in a feedhopper with the envelopes lying on one another; advancing a flexiblebelt around an elongated closed loop, said belt having one or moreraised surfaces therein adapted to jostle the bottom of the stack andreduce the envelope-to-envelope friction enabling the lowermostenvelopes to be successively transported out of said feed hopper; urgingsaid envelopes against a guide means to accurately position saidEnvelopes and enable a longitudinal edge to be cut therefrom; cutting alongitudinal edge of said envelopes as they are advanced and therebyopening said envelopes; depositing said opened envelopes in an outputhopper; applying a suction force through one or more apertures in saidbelt to hold said envelopes against said belt as said belt advances theenvelopes from said feed hopper, through said cutting operation, and toa point in the vicinity of said output hopper; and applying a greatersuction force to said envelopes in the vicinity of said feed hopper thanin the vicinities of said cutter and output hopper.